The present invention relates to a ball-point pen employing ink which is likely to cause ink column break at its initial writing, and is mainly directed to a click type writing implement incorporating a ball-point pen refill or the like which is used to correct miswriting by covering it with white ink.
Conventionally, liquid applicators using white pigments for correcting miswriting and other errors have been known.
Since the white pigments and the solvent are liable to separate, liquid applicators of this type are formed with a flexible container holding ink with a ball or the like sealed therein and they need to be shaken for mixing when used. This type of pen needs to be pressed on the container side in order to eject the ink, so it is a source of irritation that ink cannot be ejected properly by forcibly pressing the container side when a lesser amount of ink is therein. Further, this type of pen has a drawback in that ink may break or skip at its initial writing (application).
Further, attachment and removal of the cap for every usage is also cumbersome.
There also has been proposed a pressurized ball-point pen in which a pressure gas is charged on the rear end side of the ink storage after ink has been filled so as to allow the ball-point pen to write upward by utilizing the internal pressure as a result of the pressurized air charging as well as to prevent ink leakage due to backward flow of ink in the ink storage.
However, pressurized ball-point pens of this type need increased cost for charging the pressurized gas into the ink storage and complicated manufacturing equipment, hence this not only results in low productivity but also needs strict control of assembly parts, their materials and in the sealing performance at the joined portions.
Further, since the ink storage, filled up with ink, is constantly pressurized, there is a fear that a small amount of ink might leak out from the pen point. In order to avoid this, the ink needs to be increased in apparent viscosity, which will give rise to a problem of causing a dull writing sensation and other problems.
Generally, a ball-point pen using ink having a low viscosity or ink presenting thixotropy distributes a large amount of ink (in order to increase the writing density) hence has a large-diametric ink storage to store an increased amount of ink. Further, since the viscosity of such ink is relatively low compared to oil-based ball-point pen ink, its flow resistance with the ink storage is small. Therefore, ink leakage (backward flow of ink toward the rear end of the ink storage) is liable to occur by its own weight, due to being dropped or due to clicking impacts. To avoid this, a greasy follower which will move following the consumption of ink during writing and will inhibit backward flow of ink due to gravity or impacts acting on ink is deployed at the rear end of ink, with a follower rod immersed therein as necessary. However, despite the deployment of such a follower, there is still a risk of a strong backward flow of ink occurring and soiling hands and clothes when ink on the rear side of the ball in the point assembly is used up from upward writing because in this case the ink head will directly act on the follower. Further, since the viscosity of ink is low and hence an ample amount of ink flows out, this ball-point pen has the forward leakage problem, i.e., ink oozes out when the tip is placed down and a gap is formed between the tip ball and the tip holder.
The present invention has been devised in view of the above prior art, and it is therefore an object of the present invention to provide an inexpensive click type writing implement for error correction which incorporates a ball-point pen refill, such as a ball-point pen using an ink that might cause ink column break at its initial writing, for correcting miswriting by covering it with white ink, and is free from the necessity of mixing and cumbersomeness in pushing the side of the container.
In the process of solving the above problem, it was found that it is preferred that the pressure force is made different between when ink is full in the ink storage and when a lesser amount of ink is therein, or when ink column break is light and when ink column break is heavy (strong) and that an excessive amount of ink will eject out if the pressure force is too strong when ink column break is light. So the object of the present invention also includes a countermeasure against this drawback.
In order to achieve the above objects the present invention is configured as follows:
In accordance with the first aspect of the present invention, a click type writing implement comprises: a ball-pen refill composed of a point assembly at the front end thereof, an ink storage at the rear thereof and a pressurizing mechanism of a pumping type at the rear of the ink storage; and an arrangement for holding the refill and engaging it so as to allow the tip of the point assembly to be projected from and retracted into the front end, and further includes a clicking means for keeping the tip of the point assembly projected and advancing and contracting the pressurizing mechanism, the clicking means being configured so as to make the pressurizing force acting on the rear end of ink variable and promote the flow of ink toward the writing point, and is characterized in that the clicking means comprises: a first clicking means for advancing and contracting ink by a short stroke and a second clicking means for advancing and contracting ink by a large stroke, so that the rear end of ink can be pressurized at two levels.
The second aspect of the present invention resides in the click type writing implement having the above first feature, wherein the refill is configured so that the tip ball is pressed from the rear side thereof by spring pressure so as to be put into sealing contact with the inner brim of the ball holder at the tip of the point assembly and the ink storage is filled up with ink and a follower which follows the rear end of ink.
The third aspect of the present invention resides in the click type writing implement having the above first feature, wherein the pressurizing mechanism is constructed so as to release the pressure-sealed state at the rear end inside the ink storage when the tip of the point assembly is retracted, to thereby establish communication with the outside air.
The fourth aspect of the present invention resides in the click type writing implement having the above first feature, wherein the viscosity of ink is equal to or lower than 1000 mpaxc2x7s at a shearing speed of 400/s and equal to or greater than 300 mPaxc2x7S at a shearing speed of 5/s, in a 25xc2x0 C. environment.
The fifth aspect of the present invention resides in the click type writing implement having the above first feature, wherein the ink storage is filled up with a white pigment ink, which at least contains white pigments such as titanium oxide, polymer hollow particles and a gelatinizer so as to prevent sedimentation of the pigments while suppressing the loss of fluidity as low as possible.